Ligament Reconstruction Navigation for Precise Tunnel Placement

Solution Overview

Problem

Existing methods for ligament reconstruction, such as ACL reconstruction, struggle to accurately place ligament grafts to recreate a desired strain curve throughout a range of motion, as graft length and tension changes are not adequately accounted for during knee motion.

Innovation Solution

A navigation system that registers a kinematic range of motion of a joint, defines datasets representing graft length and tension, and guides the placement of tunnel apertures using a user interface to determine a desired aperture point based on selected datasets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional surgical methods are used for ligament reconstruction, then the surgical procedure can be performed, but the accuracy of tunnel aperture placement and the ability to recreate desired strain curves are insufficient

Engineering Contradiction:

Improvetunnel aperture placement accuracyVSAvoidnavigation system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The navigation system performs preliminary registration of the kinematic range of motion and defines multiple candidate tunnel aperture points before the actual graft placement. This preliminary action allows the surgeon to evaluate strain curves for different aperture locations and select the optimal position, thereby improving placement accuracy without adding excessive complexity during the critical graft insertion phase.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system provides feedback by calculating and displaying strain curves for different tunnel aperture configurations. The navigation system continuously monitors the relationship between graft length, graft tension, and knee flexion angle, allowing the surgeon to adjust aperture placement decisions based on real-time computational feedback about how each position will affect the strain curve throughout the range of motion.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If multiple candidate tunnel aperture points are evaluated, then the optimal aperture location can be determined, but the time required for registration and data definition increases

Engineering Contradiction:

Improveoptimal aperture location determinationVSAvoidregistration and data definition time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The navigation system performs preliminary registration of the kinematic range of motion and defines multiple candidate tunnel aperture points before the actual graft placement. This preliminary action allows the surgeon to evaluate strain curves for different aperture locations and select the optimal position, thereby improving placement accuracy without adding excessive complexity during the critical graft insertion phase.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system efficiently evaluates multiple candidate aperture points by changing parameters such as aperture location coordinates and calculating the resulting strain curves for each configuration. This parametric approach allows rapid comparison of different positions without requiring complete re-registration for each candidate, thus reducing the time penalty associated with evaluating multiple options.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If graft length and tension changes are not adequately accounted for, then the surgical procedure is simpler, but the ability to recreate desired strain curves throughout range of motion is compromised

Engineering Contradiction:

Improvestrain curve recreation accuracyVSAvoidnavigation and data processing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system provides feedback by calculating and displaying strain curves for different tunnel aperture configurations. The navigation system continuously monitors the relationship between graft length, graft tension, and knee flexion angle, allowing the surgeon to adjust aperture placement decisions based on real-time computational feedback about how each position will affect the strain curve throughout the range of motion.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces manual trial-and-error mechanical adjustment with computational analysis. Instead of physically creating multiple test tunnels to evaluate strain characteristics, the navigation system uses computer-based modeling to predict strain curves for different aperture positions, substituting mechanical experimentation with digital simulation and analysis.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20250308668A1Methods and systems for ligament reconstruction

Publication Date: 2025.10.02 INTELLIJOINT SURGICAL

AI summary

Methods and systems for ligament reconstruction provide navigational assistance localizing at least one desired tunnel aperture on surface of a bone of a joint. In an embodiment, each of: a kinematic range of motion of the joint, a first tunnel aperture point for a first bone and a ligament graft; and a plurality of candidate second tunnel aperture points relative to a second bone; are registered. A plurality of datasets corresponding to the plurality of candidate second tunnel aperture points are defined, where the datasets represent the relationship of either or both of a graft length or a graft tension along the kinematic range of motion. A desired second tunnel aperture point is determined in response to a selection of a desired dataset. A user interface is provided to guide a probe to a target on the bone for the desired tunnel aperture.